The spinal column is a highly complex anatomical structure capable of bearing substantial loads while displaying remarkable flexibility. A variety of conditions (e.g., traumatic, pathological, developmental, and/or degenerative) exist that may impair the load bearing capacity, flexibility, or both of a subject's spine. Under such circumstances and others, it may be desirable to attach one or more appliances to a subject's spine using one or more fasteners (e.g., screws, clamps, clips, and/or other devices). A fastener (e.g., a screw) inserted into the spine may backout of the insertion site, for example, through the course of a subject's normal activities.